1. NIDDK; LBC; Section on Carbohydrates; National Institutes of Health (NIH); Bethesda MD 20892-0815 USA
2. Department of Immunology and Infectious Diseases; Massachusetts General Hospital; 55 Fruit Street Boston MA 02114 USA
3. Laboratory of Bacterial Toxins; CBER; FDA; Silver Spring MD 20993 USA
4. International Centre for Diarrhoeal Disease Research Bangladesh; icddr; b); Dhaka Bangladesh
5. Department of Medicine; Harvard Medical School; Shattuck Street Boston MA 02115 USA
6. Department of Immunology and Infectious Diseases; Harvard School of Public Health; 677 Huntington Avenue Boston MA 02115 USA